I'm using C#, MSHTML and InternetExplorer objects to run through a webpage, but I'm snagged on an issue.
Basically, I've noticed that in IE7 or earlier, when window.showModalDialog is called, then the NewWindow3 event is triggered.
In IE8 and IE9, NewWindow3 is never triggered. As MSDN writes: "The NewWindow3 event is only fired when a new instance of Internet Explorer is about to be created. Calling showModalDialog or showModelessDialog does not trigger an event because they are not new instances of Internet Explorer. They are implemented as MSHTML host windows, which allows them to render and display HTML content but not hyperlinks between documents."
(http://msdn.microsoft.com/en-us/library/aa768337(v=VS.85).aspx)
The only way I've been able to come close to capturing the modal dialog being triggered - but I have no access to the actual modal object - is using the WindowStateChanged event. This event is routinely called, yet I've noticed that when dwFlags == 1 and dwValidFlagsMask==3, this is usually when the browser is deactivated due to a modal dialog...
Now, all I need to know is how to get that modal dialog object. Any help would be greatly appreciated
Turns out it all depends on your Windows UAC settings. For security reasons, when your UAC is set to medium or higher, UAC prevents access of modal dialogs. Lowering these settings allows full access to the modal dialog, through the NewWindow event
Related
This might be a simple question, but I have a winforms app that is loading a ChromiumWebBrowser control (CefSharp) and I can't figure out how to capture key preview events as they are all being swallowed by the control.
The standard attaching a handler to the PreviewKeyDown event of the browser control isn't working. Is there a known workaround?
CEF is run in it's own message loop, so the standard events don't work.
The first an easiest option is to implement IKeyboardHandler, you can check the CefSharp source for a more detailed example (there's one that forwards messages to the parent window if required).
Second run with settings.MultiThreadedMessageLoop = false, and call Cef.DoMessageLoopWork() on application idle, this will integrate CEF into the same message loop as your main application. Again, the source contains examples see https://github.com/cefsharp/CefSharp/blob/cefsharp/49/CefSharp.WinForms.Example/Program.cs#L63
The third option is to hook into the CEF message loop, see https://github.com/cefsharp/CefSharp/blob/cefsharp/49/CefSharp.WinForms.Example/ChromeWidgetMessageInterceptor.cs for an example
CEF = Chromium Embedded Framework - CefSharp is just a wrapper.
I have a C# application which uses a System.Windows.Forms.WebBrowser.
The problem is: i'd like the user to navigate smoothly in my application, without prompts, without javascript windows popping up, without security prompts. Even if this requires some contents to be unavailable.
I just want to have one window (always one window, if a receive a new window event, i redirect it to the single window).
How can i do this?
I tried to use this.browser.ScriptErrorsSuppressed = true but i doesnt seem to work.
For example, if i test it on a browser page which performs text validation, i still receive a popup window saying that my text is invalid.
Thank you!
I've found a solution somewhere else, since it wasn't available here.
Here it is: http://www.codeproject.com/Articles/31163/Suppressing-Hosted-WebBrowser-Control-Dialogs
Basically, you have to hook the WM_INITDIALOG message.
It works wonders here.
Msdn doc for IsolatedStorageFile.IncreaseQuotaTo states that:
To increase the quota, you must call
this method from a user-initiated
event, such as in an event handler for
a button-click event. When you call
the IncreaseQuotaTo method, the common
language runtime in Silverlight
presents a dialog box for the user to
approve the request. If the user
declines the request, this method
returns false and the quota remains
the same size.
How does Silverlight know that the method was called from a user-initiated event like a button click and not from some other thread?
More specifically: What is a user initiated event? Is there any way to overcome this limitation?
And another question:
I do some automatic downloads of files when user first accesses my application, but I don't want the user to press "Download" and then when I detect more space is needed call IncreaseQuota and have the "Silverlight dialog" appearing asking for more space.
I want to start the download automatically (not user initiated), and if I detect more space is needed, call IncreaseQuota and hence have the "Silverlight dialog" appear. (No user pressing download).
After much digging, I did find out what a user initiated event is. Seems that msdn doc specifies what a user initiated event in the section related to "events overview", but there's no link between documentation of IsolatedStorageFile.IncreaseQuotaTo and Events Overview
So a user initiated event according to the definition is:
Silverlight enforces that certain
operations are only permitted in the
context of a handler that handles a
user-initiated event. The following is
a list of such operations:
Setting IsFullScreen.
Showing certain dialogs. This includes
SaveFileDialog, OpenFileDialog, and
the print dialog displayed by
PrintDocument.Print.
Navigating from a HyperlinkButton.
Accessing the primary Clipboard API.
Silverlight user-initiated events
include the mouse events (such as
MouseLeftButtonDown), and the keyboard
events (such as KeyDown). Events of
controls that are based on such events
(such as Click) are also considered
user-initiated.
API calls that require user initiation
should be called as soon as possible
in an event handler. This is because
the Silverlight user initiation
concept also requires that the calls
occur within a certain time window
after the event occurrence. In
Silverlight 4, this time window is
approximately one second.
User-initiated event restrictions also
apply to usages of JavaScript API for
Silverlight.
When Silverlight is in full-screen
mode, some input events are
deliberately limited for security
reasons, although this can be
mitigated for out-of-browser
applications using elevated trust. For
more information, see Full-Screen
Support.
Although I don't see "IncreaseQuotaTo" inside the list of "operations", I'm guessing they just forgot it, since the behavior/limitations are the same as the ones described in the doc.
I was curios how exactly does silverlight know what a user initiated event is but after digging through .net framework source code I've got to a dead end:
if ((browserService == null) || !browserService.InPrivateMode())
{
//..
}
return false; //means that IncreaseQuota will fail
where browser.IsInPrivateMode is:
[SecuritySafeCritical]
public bool InPrivateMode()
{
bool privateMode = false;
return (NativeMethods.SUCCEEDED(UnsafeNativeMethods.DOM_InPrivateMode(this._browserServiceHandle, out privateMode)) && privateMode);
}
where DOM_InPrivateMode is in a DllImport["agcore"] which according to microsoft is confidential :(
So it looks like I won't find out soon how they're detecting user initiated events.
Thinking it more about it, I guess microsoft didn't want a user to have many tabs open in a browser and then poof: I call automatically IncreaseQuotaTo.
The IncreaseQuotaTo is a browser modal dialog. This means you can't navigate to other browser tabs while is active.
So if the user has now moved from my page to the tab with google.com, and if I would be able to call IncreaseQuotaTo with a delay, the user might think that google.com is asking for more storage :).
This would be a security breach indeed.
Had they implemented this with a page level dialog, then that would have been probably more easily hacked (or worked around).
So all in all, thinking of it, I'm starting to see why they implemented it like this and why these limitations exist.
The documentation isn't incomplete.
If I do this... button_click(..) { new UserControl() }... Does this still count as a user initiated event?
Yes. But what has that little bit of extra code really achieved?
What i've personally never experimented with is exactly what consitutes a user event; IOW is a mouse-over considered a user event? This will be very simple for you to try, and there are a multitude of other things you can experiment with. If necessary you could have a splash screen popup that welcomes the user and they have to click on it to dismiss it, at which point you make the request. It may seem a bit corny, but you can get away with things like this if you present it well.
Note that the prompt is a one-time thing. If you prompt the user and they accept, that storage is persisted for your application between visits, which means you don't need to prompt them again the next time they use your control, your quota is still increased from last time (unless the user has deliberately deleted it, which they can do by right clicking on the Silverlight control and then going to the Application Storage tab).
If you create a C# project (I'm using .NET Framework 4.0), add a WebBrowser, set ScriptErrorsSuppressed to true and navigate to http://vifprogram.com/community/ (which requires the kind of authentication that makes dialog popup for you to enter your credentials), you will get a "This program cannot display the webpage" error.
Any idea why? I tried to replicate this with Internet Explorer by switching the "Disable script debugging" in the internet options, but it works OK whether is checked or unchecked. Is there anything in IE that corresponds to WebBrowser's ScriptErrorsSuppressed? If I could at least replicate it in IE I could file a bug or something.
ScriptErrorsSuppressed suppresses not only errors, but also popup boxes such as the authentication box you refer to.
Here is an excerpt from MSDN:
When ScriptErrorsSuppressed is set to true, the WebBrowser control hides all its dialog boxes that originate from the underlying ActiveX control, not just script errors. Occasionally you might need to suppress script errors while displaying dialog boxes such as those used for browser security settings and user login. In this case, set ScriptErrorsSuppressed to false and suppress script errors in a handler for the HtmlWindow.Error event. For more information, see the code example in this topic.
http://msdn.microsoft.com/en-GB/library/system.windows.forms.webbrowser.scripterrorssuppressed.aspx
Hi i have a windows application where i show a webbrowser, i have a button that removes the browser (its a preview) and goes to another "view" in my application (another tab). My problem is that my users are getting advanced, they build HTML with links (and its ok) but the links may spawn new browser windows (IExplorer), and my button needs to close these windows, but how?
I have made some code to traverse all eht windows that ends with "Windows Internet Explorer", ahd it all seems to work - but how do i close them? I am trying to do it like this:
SendMessage((int)hWnd, WM_SYSCOMMAND, SC_CLOSE, 0);
It seems to work, but the browser pops up a dialog asking me if i want to close the tab of all the tabs...how to work around/solve this?
Cheers,
walking over all top level iE windows and closing them is a bad idea, unless you are guaranteed users can't launch ie and browse the Internet on their own. Otherwise, you might actually lose user data (say an email or a blog post the user has been working on in the last half an hour)
You can't easily work around that dialog without modifying the per-user IE settings. Your other option is to look for that dialog and click the yes button, but that would be fragile and is not guaranteed to continue working if the user upgrades to IE9.
You could potentially prevent opening links in new window by listening to BeforeNavigate event and allowing only navigations that are guaranteed to happen in your control. However, there are scenarios where IE might still decide to open new window.